The present invention relates generally to cements suitable for use with ceramic honeycomb bodies, such as for forming an outer layer on the outer periphery of the honeycomb body, or for forming plugs in the honeycomb body.
The exhaust gases emitted by internal combustion systems utilizing hydrocarbon fuels, such as hydrocarbon gases, gasoline or diesel fuel, can cause serious pollution of the atmosphere. Among the many pollutants in these exhaust gases are hydrocarbons and oxygen-containing compounds, the latter including nitrogen oxides (NOx) and carbon monoxide (CO). The automotive industry has for many years attempted to reduce the quantities of gaseous emissions from automobile engine systems. Honeycomb structures have been implemented. An outer layer or “artificial skin” or “after-applied skin” can be applied to the outer periphery of honeycomb bodies after the honeycomb bodies have been extruded. Such skin or layer is not co-extruded with the honeycomb body, but is applied after the honeycomb body has been extruded.
Defects such as cracking, separation, and delamination of the skin have been observed after catalyzation of honeycomb structures having a skin formed from known dryer-cured coatings which require only low temperatures to dry or cure, but which can begin to soften and weaken when exposed above 900° C. subsequent to drying or curing.
Known coatings have cordierite powder as a main batch component, which is produced by milling substrates or filters or matrixes designated as scrap or reject material in manufacturing. As the filter scrap level continues to decrease, owing to increased demand for cordierite reuse (powder) in manufacturing, and the demand for substrates and filters increases, a shortage of cordierite powder, and, therefore, an increased cost of goods, is eventually expected to occur.